When electrical energy accumulates in a structure of an aircraft due to a lightning stroke, static electricity or the like, a spark occurs. The occurrence of a spark may cause fuel to ignite, which may interferes with the safety of a flight. Thus, conventionally in development of an aircraft, a huge number of tests have been done in order to confirm the existence of occurrence of a spark (for example, refer to Japanese Patent Application Publication JP 2014-153298 A). As a method of confirming the existence of occurrence of a spark, a photographic method and a gas ignition confirmation method are known.
The photographic method confirms the existence of a spark by photographing a test piece in which a current flows. Meanwhile, the gas ignition confirmation method confirms the existence of ignition by supplying a current to a test piece containing a flammable gas.
Furthermore, a technique to estimate energy of a spark has also been proposed as a related technique (for example, refer to Japanese Patent Application Publication JP 2014-137227 A).
In a spark confirmation test by the photographic method, even a spark having such a small energy that the spark does not ignite becomes a ground of rejection determination in the test as long as the spark is photographed. Therefore, an excessive countermeasure for preventing occurrence of a spark may be required. Furthermore, in the photographic method, there are problems that a spark may be photographed differently when cameras are different and that it may be unable to confirm the existence of a spark in the case of photographing a test piece having a complicated structure since a photographing direction of a camera is fixed.
Meanwhile, in the case of the gas ignition confirmation method, there are problems that a test piece may ignite due to other than a spark, that a test piece may not ignite even when a spark occurs, and that the test takes long time and safety measures are necessary.
The above-mentioned conventional spark confirmation test has incurred an increase in a development period of an aircraft, and also has become a factor for increasing development costs of an aircraft. This is a common issue not only in development of an aircraft but also in development of a product for which it is necessary to prevent occurrence of a spark having explosiveness.
Thus, an object of the present invention is to provide an explosive spark estimation system and an explosive spark estimation method which allow confirming the existence of occurrence of a spark having explosiveness, more safely and simply.